HPF1-dependent PARP activation promotes LIG3-XRCC1-mediated backup pathway of Okazaki fragment ligation

Soichiro Kumamoto, Atsuya Nishiyama, Yoshie Chiba, Ryota Miyashita, Chieko Konishi, Yoshiaki Azuma, Makoto Nakanishi*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

10 Citations (Scopus)


DNA ligase 1 (LIG1) is known as the major DNA ligase responsible for Okazaki fragment joining. Recent studies have implicated LIG3 complexed with XRCC1 as an alternative player in Okazaki fragment joining in cases where LIG1 is not functional, although the underlying mechanisms are largely unknown. Here, using a cell-free system derived from Xenopus egg extracts, we demonstrated the essential role of PARP1-HPF1 in LIG3-dependent Okazaki fragment joining. We found that Okazaki fragments were eventually ligated even in the absence of LIG1, employing in its place LIG3-XRCC1, which was recruited onto chromatin. Concomitantly, LIG1 deficiency induces ADP-ribosylation of histone H3 in a PARP1-HPF1-dependent manner. The depletion of PARP1 or HPF1 resulted in a failure to recruit LIG3 onto chromatin and a subsequent failure in Okazaki fragment joining in LIG1-depleted extracts. Importantly, Okazaki fragments were not ligated at all when LIG1 and XRCC1 were co-depleted. Our results suggest that a unique form of ADP-ribosylation signaling promotes the recruitment of LIG3 on chromatin and its mediation of Okazaki fragment joining as a backup system for LIG1 perturbation.

Original languageEnglish
Pages (from-to)5003-5016
Number of pages14
JournalNucleic acids research
Issue number9
Publication statusPublished - 2021 May 21
Externally publishedYes

ASJC Scopus subject areas

  • Genetics


Dive into the research topics of 'HPF1-dependent PARP activation promotes LIG3-XRCC1-mediated backup pathway of Okazaki fragment ligation'. Together they form a unique fingerprint.

Cite this